NASA is 3D printing rocket engine parts

In case you haven’t heard, NASA is building a new rocket – a replacement for the shuttle – that will eventually take crews again outside low Earth orbit. It’s called the Space Launch System and looks surprisingly similar to the Saturn V that took men to the moon. Manufacturing technology is light years ahead of what it was in the mid-60s, and this time around NASA is printing some rocket parts with selective laser melting.

Teams at the Marshall Space Flight center are melting metal powder together with lasers to produce parts for the new J-2X engine intended for use in the earth departure stage of the Space Launch System. While the 3d-printed parts haven’t seen a use in any live fire tests of the J-2X, the goal is to test these parts out later in the year and eventually have them man-rated, to carry astronauts to the moon, asteroids, or even Mars.

This isn’t the first time 3d printing has been used to make rocket engines. Earlier this year we saw [Rocket Moonlighting] build an entire rocket engine, powered by propane and NO2, using the same technology that NASA is using. [Moonlighting]’s engine is quite small, too small to lift itself off the ground, even. Still, it’s awesome to see 3D printing that will eventually take people into solar orbit.

The don’t put documentation up because the are still a “government” organization, but I’m sure when they’re cut from the budget to make more tanks and pay for ways to dump the ones with a scratch, then we will get documentation.

These are more than likely full density stainless or nickel superalloys, the SLM process is different than the SLS process with binders and infusion. These directly melt the metal powder, rather than melting a binder and then burning it out while sintering/infusing like the prints you’re thinking of.

The lower end SLM printers (say, 100-200W laser) can already create 98% solid stainless. Takes a bit more to create full solid and inconel/monel parts, but you get the idea.

In a situation where every gram of weight counts, it seems odd to use a process that doesn’t yield the full possible metallurgical strength, and so may require more material. Though I’m sure it’s more complicated than that.

I also wonder how a porous part measures up when it comes to issues like stress corrosion cracking, hydrogen embrittlement, etc.

SLM (and EBM) processes now are at the point where they can provide the full metallurgical strength and density. Actually, there are some processes where the bulk material has better properties than conventional cast materials because you have exact control of the cooling profiles for every cubic millimeter of the part.

Chris – worth considering that if you couldn’t print the part you may have to make it much heavier (in two bits bolted together, for example) or a different shape that then causes other weight gains/headaches elsewhere in the system.

The reason it looks so much like a Saturn 5 is because it is basically. Back during the space race they were moving so fast they fought to take notes. Once NASA decided to go back to the moon they took the old Saturn 5 on display out side NASA headquarters and had to reverse engineered it. Most of the companies that made what put us into space went put of business afterwards and all the blueprints and manuals died with them.

3D printing technology really HAS come a long way, this isn’t your daddy’s SLS. You can print extremely low-tolerance, high-spec parts with SLS these days, for use in the most demanding rocket applications, and many companies do.

It’s most useful for highly complex geometries where casting doesn’t produce a consistent enough output. Things that are traditionally machined at great expense, where SLS is substantially cheaper.